CPU replacement on a MSX II

Hello,
I have an msx 2 machine from 1986.
I bought new Zilog z80 CPUs that are 10x faster than what the
original ones are are I am thinking to replace them.
What will happen?Some people told me that my computer will become
a complete speed demon.
I would like your opinion
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On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
> I have an msx 2 machine from 1986.
> I bought new Zilog z80 CPUs that are 10x faster than what the
> original ones are are I am thinking to replace them.
> What will happen?
Nothing.
It will run at the clock speed of the attached crystal as before.
> Some people told me that my computer will become
> a complete speed demon.
> I would like your opinion
They are wrong.
Running at significantly higher clock rate would require changes to the
circuit and maybe also changes to the software for I/O drivers.
Marcel

0

Marcel

12/20/2016 10:25:06 PM

On 12/20/2016 5:07 PM, Vassilios Spiliopoulos wrote:
>
> Hello,
> I have an msx 2 machine from 1986.
> I bought new Zilog z80 CPUs that are 10x faster than what the
> original ones are are I am thinking to replace them.
> What will happen?Some people told me that my computer will become
> a complete speed demon.
> I would like your opinion
It will... for very limited values of "speed demon". As Marcel pointed
out the CPU speed is set by the crystal clock, but that can be changed.
Also, a replacement might use different numbers of clock cycles to
execute instructions, so that could be faster.
But no matter what, a 10x faster Z80 is still a Z80. It won't be nearly
as fast as a Z80 emulation on a PC.
--
Rick C

0

rickman

12/21/2016 12:08:14 AM

Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>> I have an msx 2 machine from 1986.
>> I bought new Zilog z80 CPUs that are 10x faster than what the
>> original ones are are I am thinking to replace them.
>> What will happen?
>
> Nothing.
> It will run at the clock speed of the attached crystal as before.
>
>> Some people told me that my computer will become
>> a complete speed demon.
>> I would like your opinion
>
> They are wrong.
>
> Running at significantly higher clock rate would require changes to the
> circuit and maybe also changes to the software for I/O drivers.
>
>
> Marcel
>
So, the circuit will have to be modified in order to install that?
That computer's integrated OS is Microsoft BASIC.
So all applications and games for it are on .Bas format and on
waveform when in cassettes.
All these software were designed to run on a Zilog z80 @ 2.5mhz.
My new Zilog z80 is on 20 mhz.
So I guess that it will load faster?
What changes it might need?
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0

Vassilios

12/21/2016 5:36:22 AM

On 12/21/2016 12:36 AM, Vassilios Spiliopoulos wrote:
> Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>>> I have an msx 2 machine from 1986.
>>> I bought new Zilog z80 CPUs that are 10x faster than what the
>>> original ones are are I am thinking to replace them.
>>> What will happen?
>>
>> Nothing.
>> It will run at the clock speed of the attached crystal as before.
>>
>>> Some people told me that my computer will become
>>> a complete speed demon.
>>> I would like your opinion
>>
>> They are wrong.
>>
>> Running at significantly higher clock rate would require changes to the
>> circuit and maybe also changes to the software for I/O drivers.
>>
>>
>> Marcel
>>
>
> So, the circuit will have to be modified in order to install that?
> That computer's integrated OS is Microsoft BASIC.
> So all applications and games for it are on .Bas format and on
> waveform when in cassettes.
> All these software were designed to run on a Zilog z80 @ 2.5mhz.
> My new Zilog z80 is on 20 mhz.
> So I guess that it will load faster?
>
> What changes it might need?
You likely will need to recode some of the I/O routines since they
likely use timing loops to establish wait times. Tape interfaces are
typically time oriented to recover the data. If you speed up the CPU it
will shorten the time loops causing the interface to fail.
If this drives a video interface, it likely is also dependent on timing
by the CPU. Often they used a line frequency interrupt which triggered
the CPU to output the bytes to the screen with a set timing.
I did a little reading and it seems they used the V9938 video display
chip. I expect this handles all the video timing, so as long as the
clock to the video circuits remains the same, that should continue to work.
You really need to get more info on how the system was designed. I see
this was not one machine from one company, but rather a general computer
spec that many companies built computers to. I see mentioned a 1chipMSX
which was the entire computer logic in an FPGA. That would give you all
the info you need if you could find the design documents for it. It
also should put your 20 MHz Z80 to shame if you can find one. An FPGA
implementation could potentially run at 50 to 100 MHz.
It looks like there are blogs and other info available on the Internet.
Maybe there are still some active groups?
Here is an interesting link giving a brief overview of the MSX history.
http://www.dvorak.org/blog/whatever-happened-to-msx-computers/
--
Rick C

0

rickman

12/21/2016 6:08:37 AM

rickman <gnuarm@gmail.com> Wrote in message:
> On 12/21/2016 12:36 AM, Vassilios Spiliopoulos wrote:
>> Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>>> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>>>> I have an msx 2 machine from 1986.
>>>> I bought new Zilog z80 CPUs that are 10x faster than what the
>>>> original ones are are I am thinking to replace them.
>>>> What will happen?
>>>
>>> Nothing.
>>> It will run at the clock speed of the attached crystal as before.
>>>
>>>> Some people told me that my computer will become
>>>> a complete speed demon.
>>>> I would like your opinion
>>>
>>> They are wrong.
>>>
>>> Running at significantly higher clock rate would require changes to the
>>> circuit and maybe also changes to the software for I/O drivers.
>>>
>>>
>>> Marcel
>>>
>>
>> So, the circuit will have to be modified in order to install that?
>> That computer's integrated OS is Microsoft BASIC.
>> So all applications and games for it are on .Bas format and on
>> waveform when in cassettes.
>> All these software were designed to run on a Zilog z80 @ 2.5mhz.
>> My new Zilog z80 is on 20 mhz.
>> So I guess that it will load faster?
>>
>> What changes it might need?
>
> You likely will need to recode some of the I/O routines since they
> likely use timing loops to establish wait times. Tape interfaces are
> typically time oriented to recover the data. If you speed up the CPU it
> will shorten the time loops causing the interface to fail.
>
> If this drives a video interface, it likely is also dependent on timing
> by the CPU. Often they used a line frequency interrupt which triggered
> the CPU to output the bytes to the screen with a set timing.
>
> I did a little reading and it seems they used the V9938 video display
> chip. I expect this handles all the video timing, so as long as the
> clock to the video circuits remains the same, that should continue to work.
>
> You really need to get more info on how the system was designed. I see
> this was not one machine from one company, but rather a general computer
> spec that many companies built computers to. I see mentioned a 1chipMSX
> which was the entire computer logic in an FPGA. That would give you all
> the info you need if you could find the design documents for it. It
> also should put your 20 MHz Z80 to shame if you can find one. An FPGA
> implementation could potentially run at 50 to 100 MHz.
>
> It looks like there are blogs and other info available on the Internet.
> Maybe there are still some active groups?
>
> Here is an interesting link giving a brief overview of the MSX history.
>
> http://www.dvorak.org/blog/whatever-happened-to-msx-computers/
>
> --
>
> Rick C
>
It is a Phillips NMS machine
So the speed won't be much different due to the clock ?
Also are the pinouts changed?
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0

Vassilios

12/21/2016 8:29:37 AM

On Wednesday, December 21, 2016 at 12:29:45 AM UTC-8, Vassilios Spiliopoulos wrote:
> rickman <gnuarm@gmail.com> Wrote in message:
> > On 12/21/2016 12:36 AM, Vassilios Spiliopoulos wrote:
> >> Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
> >>> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
> >>>> I have an msx 2 machine from 1986.
> >>>> I bought new Zilog z80 CPUs that are 10x faster than what the
> >>>> original ones are are I am thinking to replace them.
> >>>> What will happen?
> >>>
> >>> Nothing.
> >>> It will run at the clock speed of the attached crystal as before.
> >>>
> >>>> Some people told me that my computer will become
> >>>> a complete speed demon.
> >>>> I would like your opinion
> >>>
> >>> They are wrong.
> >>>
> >>> Running at significantly higher clock rate would require changes to the
> >>> circuit and maybe also changes to the software for I/O drivers.
> >>>
> >>>
> >>> Marcel
> >>>
> >>
> >> So, the circuit will have to be modified in order to install that?
> >> That computer's integrated OS is Microsoft BASIC.
> >> So all applications and games for it are on .Bas format and on
> >> waveform when in cassettes.
> >> All these software were designed to run on a Zilog z80 @ 2.5mhz.
> >> My new Zilog z80 is on 20 mhz.
> >> So I guess that it will load faster?
> >>
> >> What changes it might need?
> >
> > You likely will need to recode some of the I/O routines since they
> > likely use timing loops to establish wait times. Tape interfaces are
> > typically time oriented to recover the data. If you speed up the CPU it
> > will shorten the time loops causing the interface to fail.
> >
> > If this drives a video interface, it likely is also dependent on timing
> > by the CPU. Often they used a line frequency interrupt which triggered
> > the CPU to output the bytes to the screen with a set timing.
> >
> > I did a little reading and it seems they used the V9938 video display
> > chip. I expect this handles all the video timing, so as long as the
> > clock to the video circuits remains the same, that should continue to work.
> >
> > You really need to get more info on how the system was designed. I see
> > this was not one machine from one company, but rather a general computer
> > spec that many companies built computers to. I see mentioned a 1chipMSX
> > which was the entire computer logic in an FPGA. That would give you all
> > the info you need if you could find the design documents for it. It
> > also should put your 20 MHz Z80 to shame if you can find one. An FPGA
> > implementation could potentially run at 50 to 100 MHz.
> >
> > It looks like there are blogs and other info available on the Internet.
> > Maybe there are still some active groups?
> >
> > Here is an interesting link giving a brief overview of the MSX history.
> >
> > http://www.dvorak.org/blog/whatever-happened-to-msx-computers/
> >
> > --
> >
> > Rick C
> >
>
> It is a Phillips NMS machine
> So the speed won't be much different due to the clock ?
>
> Also are the pinouts changed?
> --
>
>
> ----Android NewsGroup Reader----
> http://usenet.sinaapp.com/
I think you would get a lot more interest in your posts on sci.electronics.design .

0

Mark

12/21/2016 3:58:20 PM

On Wed, 21 Dec 2016 07:36:22 +0200, Vassilios Spiliopoulos wrote:
> Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>>> I have an msx 2 machine from 1986.
>>> I bought new Zilog z80 CPUs that are 10x faster than what the
>>> original ones are are I am thinking to replace them.
>>> What will happen?
>>
>> Nothing.
>> It will run at the clock speed of the attached crystal as before.
>>
>>> Some people told me that my computer will become
>>> a complete speed demon.
>>> I would like your opinion
>>
>> They are wrong.
>>
>> Running at significantly higher clock rate would require changes to the
>> circuit and maybe also changes to the software for I/O drivers.
>>
>>
>> Marcel
>>
>>
> So, the circuit will have to be modified in order to install that?
> That computer's integrated OS is Microsoft BASIC.
> So all applications and games for it are on .Bas format and on
> waveform when in cassettes.
> All these software were designed to run on a Zilog z80 @ 2.5mhz. My new
> Zilog z80 is on 20 mhz.
> So I guess that it will load faster?
> What changes it might need?
So, here's the deal:
If you just put the chip in and don't change anything else, then there's
a good chance that it'll work the same. Maybe a bit faster if the new Z80
makes more efficient use of clock cycles, but probably the same.
You could boost the clock speed to 20MHz with appropriate changes to the
oscillator circuit, but it's almost certain that your external memory and
peripherals won't be able to keep up, because they're from the same era
and price class as that 2MHz CPU.
Even if you could just change the clock circuit, then you'd probably mess
up whatever real-time aspects of the computer are there. This might be
limited to the time-of-day clock going through an hour in 8 minutes, but
if the thing generates video it might mean that your video will be
totally screwed up. That computer's from an era where pauses in
execution were timed by software delay loops, and those would be screwed
up as well, so there's a good chance that any games would be screwed up.
If you had some significant circuit design and software chops, and you
had access to the original software, then you could make the change --
but you'd essentially be redesigning the whole computer. There's a good
chance that even if you could get all the right parts that would fit in
all the right holes on the board that you'd run into board limitations.
Sorry to be so negative. If you want to try it out, go ahead. You'll
learn something, and that's always worthwhile.
--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

0

Tim

12/21/2016 6:09:12 PM

On Wednesday, December 21, 2016 at 8:09:20 PM UTC+2, Tim Wescott wrote:
> On Wed, 21 Dec 2016 07:36:22 +0200, Vassilios Spiliopoulos wrote:
>
> > Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
> >> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
> >>> I have an msx 2 machine from 1986.
> >>> I bought new Zilog z80 CPUs that are 10x faster than what the
> >>> original ones are are I am thinking to replace them.
> >>> What will happen?
> >>
> >> Nothing.
> >> It will run at the clock speed of the attached crystal as before.
> >>
> >>> Some people told me that my computer will become
> >>> a complete speed demon.
> >>> I would like your opinion
> >>
> >> They are wrong.
> >>
> >> Running at significantly higher clock rate would require changes to the
> >> circuit and maybe also changes to the software for I/O drivers.
> >>
> >>
> >> Marcel
> >>
> >>
> > So, the circuit will have to be modified in order to install that?
> > That computer's integrated OS is Microsoft BASIC.
> > So all applications and games for it are on .Bas format and on
> > waveform when in cassettes.
> > All these software were designed to run on a Zilog z80 @ 2.5mhz. My new
> > Zilog z80 is on 20 mhz.
> > So I guess that it will load faster?
> > What changes it might need?
>
> So, here's the deal:
>
> If you just put the chip in and don't change anything else, then there's
> a good chance that it'll work the same. Maybe a bit faster if the new Z80
> makes more efficient use of clock cycles, but probably the same.
>
> You could boost the clock speed to 20MHz with appropriate changes to the
> oscillator circuit, but it's almost certain that your external memory and
> peripherals won't be able to keep up, because they're from the same era
> and price class as that 2MHz CPU.
>
> Even if you could just change the clock circuit, then you'd probably mess
> up whatever real-time aspects of the computer are there. This might be
> limited to the time-of-day clock going through an hour in 8 minutes, but
> if the thing generates video it might mean that your video will be
> totally screwed up. That computer's from an era where pauses in
> execution were timed by software delay loops, and those would be screwed
> up as well, so there's a good chance that any games would be screwed up.
>
> If you had some significant circuit design and software chops, and you
> had access to the original software, then you could make the change --
> but you'd essentially be redesigning the whole computer. There's a good
> chance that even if you could get all the right parts that would fit in
> all the right holes on the board that you'd run into board limitations.
>
> Sorry to be so negative. If you want to try it out, go ahead. You'll
> learn something, and that's always worthwhile.
>
> --
> Tim Wescott
> Control systems, embedded software and circuit design
> I'm looking for work! See my website if you're interested
> http://www.wescottdesign.com
I see.
What I was afraid of was if I risk anything, for example if I risk to destroy the computer...We are talking about rare stuff...

0

yassilis00

12/21/2016 7:03:57 PM

On Wed, 21 Dec 2016 11:03:57 -0800, yassilis00 wrote:
> On Wednesday, December 21, 2016 at 8:09:20 PM UTC+2, Tim Wescott wrote:
>> On Wed, 21 Dec 2016 07:36:22 +0200, Vassilios Spiliopoulos wrote:
>>
>> > Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>> >> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>> >>> I have an msx 2 machine from 1986.
>> >>> I bought new Zilog z80 CPUs that are 10x faster than what the
>> >>> original ones are are I am thinking to replace them.
>> >>> What will happen?
>> >>
>> >> Nothing.
>> >> It will run at the clock speed of the attached crystal as before.
>> >>
>> >>> Some people told me that my computer will become
>> >>> a complete speed demon.
>> >>> I would like your opinion
>> >>
>> >> They are wrong.
>> >>
>> >> Running at significantly higher clock rate would require changes to
>> >> the circuit and maybe also changes to the software for I/O drivers.
>> >>
>> >>
>> >> Marcel
>> >>
>> >>
>> > So, the circuit will have to be modified in order to install that?
>> > That computer's integrated OS is Microsoft BASIC.
>> > So all applications and games for it are on .Bas format and on
>> > waveform when in cassettes.
>> > All these software were designed to run on a Zilog z80 @ 2.5mhz. My
>> > new Zilog z80 is on 20 mhz.
>> > So I guess that it will load faster?
>> > What changes it might need?
>>
>> So, here's the deal:
>>
>> If you just put the chip in and don't change anything else, then
>> there's a good chance that it'll work the same. Maybe a bit faster if
>> the new Z80 makes more efficient use of clock cycles, but probably the
>> same.
>>
>> You could boost the clock speed to 20MHz with appropriate changes to
>> the oscillator circuit, but it's almost certain that your external
>> memory and peripherals won't be able to keep up, because they're from
>> the same era and price class as that 2MHz CPU.
>>
>> Even if you could just change the clock circuit, then you'd probably
>> mess up whatever real-time aspects of the computer are there. This
>> might be limited to the time-of-day clock going through an hour in 8
>> minutes, but if the thing generates video it might mean that your video
>> will be totally screwed up. That computer's from an era where pauses
>> in execution were timed by software delay loops, and those would be
>> screwed up as well, so there's a good chance that any games would be
>> screwed up.
>>
>> If you had some significant circuit design and software chops, and you
>> had access to the original software, then you could make the change --
>> but you'd essentially be redesigning the whole computer. There's a
>> good chance that even if you could get all the right parts that would
>> fit in all the right holes on the board that you'd run into board
>> limitations.
>>
>> Sorry to be so negative. If you want to try it out, go ahead. You'll
>> learn something, and that's always worthwhile.
>>
>> --
>> Tim Wescott Control systems, embedded software and circuit design I'm
>> looking for work! See my website if you're interested
>> http://www.wescottdesign.com
>
> I see.
> What I was afraid of was if I risk anything, for example if I risk to
> destroy the computer...We are talking about rare stuff...
If the chip is soldered in and things work now, I would strongly suggest
that you leave it alone. Particularly if the board has plated-through
holes (it almost certainly has two or more layers) then it takes
considerable expertise to get the chip out without damaging the board.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
I'm looking for work -- see my website!

0

Tim

12/21/2016 7:17:03 PM

Tim Wescott <seemywebsite@myfooter.really> Wrote in message:
> On Wed, 21 Dec 2016 11:03:57 -0800, yassilis00 wrote:
>
>> On Wednesday, December 21, 2016 at 8:09:20 PM UTC+2, Tim Wescott wrote:
>>> On Wed, 21 Dec 2016 07:36:22 +0200, Vassilios Spiliopoulos wrote:
>>>
>>> > Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>>> >> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>>> >>> I have an msx 2 machine from 1986.
>>> >>> I bought new Zilog z80 CPUs that are 10x faster than what the
>>> >>> original ones are are I am thinking to replace them.
>>> >>> What will happen?
>>> >>
>>> >> Nothing.
>>> >> It will run at the clock speed of the attached crystal as before.
>>> >>
>>> >>> Some people told me that my computer will become
>>> >>> a complete speed demon.
>>> >>> I would like your opinion
>>> >>
>>> >> They are wrong.
>>> >>
>>> >> Running at significantly higher clock rate would require changes to
>>> >> the circuit and maybe also changes to the software for I/O drivers.
>>> >>
>>> >>
>>> >> Marcel
>>> >>
>>> >>
>>> > So, the circuit will have to be modified in order to install that?
>>> > That computer's integrated OS is Microsoft BASIC.
>>> > So all applications and games for it are on .Bas format and on
>>> > waveform when in cassettes.
>>> > All these software were designed to run on a Zilog z80 @ 2.5mhz. My
>>> > new Zilog z80 is on 20 mhz.
>>> > So I guess that it will load faster?
>>> > What changes it might need?
>>>
>>> So, here's the deal:
>>>
>>> If you just put the chip in and don't change anything else, then
>>> there's a good chance that it'll work the same. Maybe a bit faster if
>>> the new Z80 makes more efficient use of clock cycles, but probably the
>>> same.
>>>
>>> You could boost the clock speed to 20MHz with appropriate changes to
>>> the oscillator circuit, but it's almost certain that your external
>>> memory and peripherals won't be able to keep up, because they're from
>>> the same era and price class as that 2MHz CPU.
>>>
>>> Even if you could just change the clock circuit, then you'd probably
>>> mess up whatever real-time aspects of the computer are there. This
>>> might be limited to the time-of-day clock going through an hour in 8
>>> minutes, but if the thing generates video it might mean that your video
>>> will be totally screwed up. That computer's from an era where pauses
>>> in execution were timed by software delay loops, and those would be
>>> screwed up as well, so there's a good chance that any games would be
>>> screwed up.
>>>
>>> If you had some significant circuit design and software chops, and you
>>> had access to the original software, then you could make the change --
>>> but you'd essentially be redesigning the whole computer. There's a
>>> good chance that even if you could get all the right parts that would
>>> fit in all the right holes on the board that you'd run into board
>>> limitations.
>>>
>>> Sorry to be so negative. If you want to try it out, go ahead. You'll
>>> learn something, and that's always worthwhile.
>>>
>>> --
>>> Tim Wescott Control systems, embedded software and circuit design I'm
>>> looking for work! See my website if you're interested
>>> http://www.wescottdesign.com
>>
>> I see.
>> What I was afraid of was if I risk anything, for example if I risk to
>> destroy the computer...We are talking about rare stuff...
>
> If the chip is soldered in and things work now, I would strongly suggest
> that you leave it alone. Particularly if the board has plated-through
> holes (it almost certainly has two or more layers) then it takes
> considerable expertise to get the chip out without damaging the board.
>
> --
>
> Tim Wescott
> Wescott Design Services
> http://www.wescottdesign.com
>
> I'm looking for work -- see my website!
>
Yes, the CPU is soldered
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0

Vassilios

12/23/2016 9:44:59 PM

On Fri, 23 Dec 2016 23:44:59 +0200, Vassilios Spiliopoulos wrote:
> Tim Wescott <seemywebsite@myfooter.really> Wrote in message:
>> On Wed, 21 Dec 2016 11:03:57 -0800, yassilis00 wrote:
>>
>>> On Wednesday, December 21, 2016 at 8:09:20 PM UTC+2, Tim Wescott
>>> wrote:
>>>> On Wed, 21 Dec 2016 07:36:22 +0200, Vassilios Spiliopoulos wrote:
>>>>
>>>> > Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>>>> >> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>>>> >>> I have an msx 2 machine from 1986.
>>>> >>> I bought new Zilog z80 CPUs that are 10x faster than what the
>>>> >>> original ones are are I am thinking to replace them.
>>>> >>> What will happen?
>>>> >>
>>>> >> Nothing.
>>>> >> It will run at the clock speed of the attached crystal as before.
>>>> >>
>>>> >>> Some people told me that my computer will become
>>>> >>> a complete speed demon.
>>>> >>> I would like your opinion
>>>> >>
>>>> >> They are wrong.
>>>> >>
>>>> >> Running at significantly higher clock rate would require changes
>>>> >> to the circuit and maybe also changes to the software for I/O
>>>> >> drivers.
>>>> >>
>>>> >>
>>>> >> Marcel
>>>> >>
>>>> >>
>>>> > So, the circuit will have to be modified in order to install that?
>>>> > That computer's integrated OS is Microsoft BASIC.
>>>> > So all applications and games for it are on .Bas format and on
>>>> > waveform when in cassettes.
>>>> > All these software were designed to run on a Zilog z80 @ 2.5mhz. My
>>>> > new Zilog z80 is on 20 mhz.
>>>> > So I guess that it will load faster?
>>>> > What changes it might need?
>>>>
>>>> So, here's the deal:
>>>>
>>>> If you just put the chip in and don't change anything else, then
>>>> there's a good chance that it'll work the same. Maybe a bit faster
>>>> if the new Z80 makes more efficient use of clock cycles, but probably
>>>> the same.
>>>>
>>>> You could boost the clock speed to 20MHz with appropriate changes to
>>>> the oscillator circuit, but it's almost certain that your external
>>>> memory and peripherals won't be able to keep up, because they're from
>>>> the same era and price class as that 2MHz CPU.
>>>>
>>>> Even if you could just change the clock circuit, then you'd probably
>>>> mess up whatever real-time aspects of the computer are there. This
>>>> might be limited to the time-of-day clock going through an hour in 8
>>>> minutes, but if the thing generates video it might mean that your
>>>> video will be totally screwed up. That computer's from an era where
>>>> pauses in execution were timed by software delay loops, and those
>>>> would be screwed up as well, so there's a good chance that any games
>>>> would be screwed up.
>>>>
>>>> If you had some significant circuit design and software chops, and
>>>> you had access to the original software, then you could make the
>>>> change -- but you'd essentially be redesigning the whole computer.
>>>> There's a good chance that even if you could get all the right parts
>>>> that would fit in all the right holes on the board that you'd run
>>>> into board limitations.
>>>>
>>>> Sorry to be so negative. If you want to try it out, go ahead.
>>>> You'll learn something, and that's always worthwhile.
>>>>
>>>> --
>>>> Tim Wescott Control systems, embedded software and circuit design I'm
>>>> looking for work! See my website if you're interested
>>>> http://www.wescottdesign.com
>>>
>>> I see.
>>> What I was afraid of was if I risk anything, for example if I risk to
>>> destroy the computer...We are talking about rare stuff...
>>
>> If the chip is soldered in and things work now, I would strongly
>> suggest that you leave it alone. Particularly if the board has
>> plated-through holes (it almost certainly has two or more layers) then
>> it takes considerable expertise to get the chip out without damaging
>> the board.
>>
>> --
>>
>> Tim Wescott Wescott Design Services http://www.wescottdesign.com
>>
>> I'm looking for work -- see my website!
>>
>>
> Yes, the CPU is soldered
I wouldn't touch it then.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
I'm looking for work -- see my website!

0

Tim

12/23/2016 9:54:57 PM

On 12/23/2016 4:54 PM, Tim Wescott wrote:
> On Fri, 23 Dec 2016 23:44:59 +0200, Vassilios Spiliopoulos wrote:
>
>> Tim Wescott <seemywebsite@myfooter.really> Wrote in message:
>>> On Wed, 21 Dec 2016 11:03:57 -0800, yassilis00 wrote:
>>>
>>>> On Wednesday, December 21, 2016 at 8:09:20 PM UTC+2, Tim Wescott
>>>> wrote:
>>>>> On Wed, 21 Dec 2016 07:36:22 +0200, Vassilios Spiliopoulos wrote:
>>>>>
>>>>>> Marcel Mueller <news.5.maazl@spamgourmet.org> Wrote in message:
>>>>>>> On 20.12.16 23.07, Vassilios Spiliopoulos wrote:
>>>>>>>> I have an msx 2 machine from 1986.
>>>>>>>> I bought new Zilog z80 CPUs that are 10x faster than what the
>>>>>>>> original ones are are I am thinking to replace them.
>>>>>>>> What will happen?
>>>>>>>
>>>>>>> Nothing.
>>>>>>> It will run at the clock speed of the attached crystal as before.
>>>>>>>
>>>>>>>> Some people told me that my computer will become
>>>>>>>> a complete speed demon.
>>>>>>>> I would like your opinion
>>>>>>>
>>>>>>> They are wrong.
>>>>>>>
>>>>>>> Running at significantly higher clock rate would require changes
>>>>>>> to the circuit and maybe also changes to the software for I/O
>>>>>>> drivers.
>>>>>>>
>>>>>>>
>>>>>>> Marcel
>>>>>>>
>>>>>>>
>>>>>> So, the circuit will have to be modified in order to install that?
>>>>>> That computer's integrated OS is Microsoft BASIC.
>>>>>> So all applications and games for it are on .Bas format and on
>>>>>> waveform when in cassettes.
>>>>>> All these software were designed to run on a Zilog z80 @ 2.5mhz. My
>>>>>> new Zilog z80 is on 20 mhz.
>>>>>> So I guess that it will load faster?
>>>>>> What changes it might need?
>>>>>
>>>>> So, here's the deal:
>>>>>
>>>>> If you just put the chip in and don't change anything else, then
>>>>> there's a good chance that it'll work the same. Maybe a bit faster
>>>>> if the new Z80 makes more efficient use of clock cycles, but probably
>>>>> the same.
>>>>>
>>>>> You could boost the clock speed to 20MHz with appropriate changes to
>>>>> the oscillator circuit, but it's almost certain that your external
>>>>> memory and peripherals won't be able to keep up, because they're from
>>>>> the same era and price class as that 2MHz CPU.
>>>>>
>>>>> Even if you could just change the clock circuit, then you'd probably
>>>>> mess up whatever real-time aspects of the computer are there. This
>>>>> might be limited to the time-of-day clock going through an hour in 8
>>>>> minutes, but if the thing generates video it might mean that your
>>>>> video will be totally screwed up. That computer's from an era where
>>>>> pauses in execution were timed by software delay loops, and those
>>>>> would be screwed up as well, so there's a good chance that any games
>>>>> would be screwed up.
>>>>>
>>>>> If you had some significant circuit design and software chops, and
>>>>> you had access to the original software, then you could make the
>>>>> change -- but you'd essentially be redesigning the whole computer.
>>>>> There's a good chance that even if you could get all the right parts
>>>>> that would fit in all the right holes on the board that you'd run
>>>>> into board limitations.
>>>>>
>>>>> Sorry to be so negative. If you want to try it out, go ahead.
>>>>> You'll learn something, and that's always worthwhile.
>>>>>
>>>>> --
>>>>> Tim Wescott Control systems, embedded software and circuit design I'm
>>>>> looking for work! See my website if you're interested
>>>>> http://www.wescottdesign.com
>>>>
>>>> I see.
>>>> What I was afraid of was if I risk anything, for example if I risk to
>>>> destroy the computer...We are talking about rare stuff...
>>>
>>> If the chip is soldered in and things work now, I would strongly
>>> suggest that you leave it alone. Particularly if the board has
>>> plated-through holes (it almost certainly has two or more layers) then
>>> it takes considerable expertise to get the chip out without damaging
>>> the board.
>>>
>>> --
>>>
>>> Tim Wescott Wescott Design Services http://www.wescottdesign.com
>>>
>>> I'm looking for work -- see my website!
>>>
>>>
>> Yes, the CPU is soldered
>
> I wouldn't touch it then.
If you want a faster computer look for an emulator on the PC. If you
want faster hardware, look for the version of your MSX II with an FPGA.
If you want a learning challenge, learn to program up your MSX II
computer on an FPGA board.
--
Rick C